Recently, this error was encountered in coding: local variable ‘XXX’ Referenced before assignment, which solved this problem by looking up materials. This blog is very clear, so I collect it for you to view later.

Referenced Before Assignment Local Variable ‘XXX’ Referenced Before Assignment Local Variable ‘XXX’ Referenced Before Assignment Local Variable ‘XXX’ Referenced Before Assignment

[python] view plain copy
xxx = 23  
def PrintFileName(strFileName):   
    if xxx == 23:  
        print strFileName  
        xxx = 24  

PrintFileName("file")  

Error means that the variable ‘XXX’ is not defined before the reference. The global keyword in Python is used to refer to global variables, so I tried it, and it worked: * * * * * * * * * * * * * * * * * * * *

[python] view plain copy
xxx = 23  
def PrintFileName(strFileName):  
    global xxx  
    if xxx == 23:  
        print strFileName  
        xxx = 24  

PrintFileName("file")  

In Python, if you change the value of a variable with the same global name, it will become a local variable. The reference to that variable will be undefined before you change it. If you want to reference a global variable, and if you want to change it, you must include the global keyword.
The original link: http://blog.csdn.net/magictong/article/details/4464024

Added:
defines global variables in the class:

a = 1 
class File(object): 
    def printString(self,str): 
        global a  
        if a == 1:  
            print str  
            a = 24          
f = File()             
f.printString("file")  

 with open(json_file) as anno_file:
        anno = json.load(anno_file)

, an error:
json. The decoder. JSONDecodeError: Extra data: line 1 column 57054 char (57053)

 
Reason 2.
according to the prompt, the reason should be the json file of each line there is a limit to the number character (not more than 57053), but my line too much content
 

>
>
>
>
>
>
>

 with open(file_write, "w+") as f:
        for infor in dict_w[index]:
            dict_w1 = {infor: dict_w[index][infor]}
            json.dump(dict_w1, f)
            f.write("\n")

 
4. Further problems
run again at the beginning of reading and an error while reading code:
json. The decoder. JSONDecodeError: Extra data: line 2 column 1 (135) char

 

on. Load does not support decoding multiple JSON objects: Json. Loads , and json. The load ) does not decode multiple json object.